Zhao R, Zhang B, Sun J, Zheng Z, Qiao X. Evaluation of degradation of pigments formed during garlic discoloration in different pH.
Food Res Int 2021;
140:109957. [PMID:
33648209 DOI:
10.1016/j.foodres.2020.109957]
[Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 10/20/2020] [Accepted: 11/27/2020] [Indexed: 11/19/2022]
Abstract
The specific chemical bond changes of green pigment formed in garlic discoloration were investigated in our study. Multiple analysis methods were used in the degradation of pigment, including ultraviolet-visible (UV-Vis) spectrophotometry, attenuated total reflection Fourier transform infrared (ATR-FTIR) and Fourier transform infrared near infrared (FT-NIR). Green pigments were treated at 40 °C for 7 days in the pH range of 5.0-8.0. Principal component analysis of the ATR-FTIR and FT-NIR spectra indicated the similarities and differences during pigment degradation. It was found that the degradation degree of green pigments in a solution with pH 5.0 was the lowest. Changes in the absorptions of CO, COO-, CN, CN, OCOCH, COC, COOH, and NH bonds vibrations are attributed to the decomposition of the pigments. The absorption at 5170 cm-1 (NH bond first overtone) and 4871 cm-1 (OCH stretching) correlated to pigment degradation were confirmed by FT-NIR spectra. One proposed pathway of the pigment decomposition was explored.
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